Greetings fellow earthlings. My 2011 XJ 5.0 Portfolio has got the nagging 'washer fluid low' warning light coming on. At first was intermittent and now is on all the time. The sensor was reading several kohms when the switch was closed so replaced it with a new one (which I tested first - zero ohms when closed) and still got the fault. Disconnected the battery thinking a hard reset might clear it, even reset the CAN modules to no avail. Voltage at the plug behind the wheel arch liner is only 0.8 volts and there's no break in the cable which leaves the central junction box as the only other thing I can think of. Have removed it, cleaned all the contacts and fuses and didn't spot any corrosion or water ingress when I removed the covers so I suspect a component has died or shorted out.

If I replace the CJB with the same model from a donor car does it need to be reprogrammed or will it self-learn from the other modules in the car? I have a NT520 diagnostic unit which will enable me to recalibrate a number of items. I know it's a minor thing that can be fixed by pushing OK on the steering wheel but I like everything to work (it's the OCD in me). Thanks in advance.

 

To replace a CJB with a used one you'll need to do a following with a SDD:
-immobilization, otherwise there'll be no start/no ignition
-reload a CCF
and after that a CJB will still have a wrong VIN number, at least untill you reprog it with a special device (and there's a bit of soldering required)

 

Sounds like it's in the too hard basket. My soldering skills are fine being a ex electronics engineer, but procuring the hardware for such a trivial issue suggests I just leave the damn thing....

 

I took my 2013 XJ to the dealer for a recurring "Washer Fluid Low" warning light. The technician couldn't find a leak anywhere, and my service advisor explained that the float valve in the reservoir can be triggered when the front of the car is on an uphill incline. He also explained that the washer reservoir is in 2 sections that snap together, but don't have a watertight seal at that point, so when you fill the tank to the very top it will slowly leak out at that joint and when you open the cap it will appear to need more fluid.

I decided to verify this while still at my dealer. I knew that the reservoir was filled to capacity, so I drove to the part of his parking lot that had a steep incline, parked, and then restarted the car. The warning light came on immediately, even though the reservoir was full. I opened the fill cap and it appeared to need more fluid, but I knew it was far from being empty.

Just another one of those things that makes Jaguar a Jaguar!

 

Yes one of the joys of owning such a beast! I was hoping I could disable the status indicator on the display with my NT520 pro but from the previous post it's definitely more involved (and more $$) obtaining the gear to reprogram etc. Maybe some blackout tape on the bottom right of the instrument display is cheaper lol

 

No need to produce devices, but some good programmer is needed (like Orange-5, e.t.c), which is able to read/write secured motorolla chips.

 

I have had the same issue with my 2013 XF portfolio The other issue that started happening at same time was the sporadic locking and unlocking of the doors. Unfortunately getting this CJB wiring replaced at the dealer will cost close to half the value of the car! I am afraid an independent local garage might introduce other issues 😔

 

You have an XF this is the XJ forum?
Yes the XF suffers from a whole array of CJB problems that the XJ does not.
Different car with different problems.
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This company offers both a water damage and no key recognition service.

https://motortronics.co.uk/product/xf-bcm-water-damage/

Has anyone tried them?

 

Good find!
I hope someone posts back as a repair would be way cheaper than a new replacement!
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They are in the U.K.